The present invention relates to a directional control apparatus for flowing media, especially a switch valve for the exhaust gages of an internal combustion engine, having a housing part in which an inlet and a first outlet and a second outlet are formed, and having a directional control member in the form of a swinging flap by which either the first outlet or the second outlet may selectively be closed, as a result of which the respective other outlet is in connection with the inlet.
In order, for example, for it to be possible to use the exhaust-gas heat of internal combustion engines to heat up a cooler medium, or in order to reduce the emission levels of the emerging gases, it is necessary for the gases, at least intermittently, to flow through a heat exchanger, a NOx converter acting by catalysis, a NOx storage catalyst, a particle filter, an absorber or other special components. A method of this type and an appropriate apparatus are described, for example, in DE 195 26 765. In accordance with this known technical solution, flap valves are provided both in a main line and in a bypass line and are opened and closed alternately, but separately in each case.
As separate valves in different lines require a high design input, directional control apparatuses have been described for similar purposes that are also described as switch valves, with which it is possible simultaneously with the opening of one line of the flowing medium to shut off another line. Such an apparatus of this type is known, for example, from U.S. Pat. No. 5,410,876, which describes a catalytic converter assembly with a bypass. According to one of the embodiments shown therein, a swinging flap is provided, by means of which a first or a second outlet can selectively be shut off. When this occurs, the flap projects into the region of the inlet and, in each of its two possible end positions, lies against one of the side walls of the inlet. The assembly is very compact and requires a high level of accuracy in production—not only for the flap but also for the contact surfaces on the inlet wall.